Looks like 8 legs to me. I noticed quite a few large wolf type spiders within roots of undercuts on a stream I visited last week. That one is lighter and smoother so maybe not a "fishing" spider but I'm no expert.

Def looks like a wolf spider and not a water strider. Didn't know they could walk on water though. I've seen some big ones around my house in the last few years. I wouldn't doubt a fish would eat that.

It was definitely a spider. I was very surprised how agile it was on the surface of the water. This thing was huge, the distance between the tips of its legs was somewhere between 3 and 4 inches. Wish I had something in the picture to show some scale. This is no exaggeration, one of the biggest spiders I have ever seen in the wild.